Data may be transferred between computers in a variety of ways. File sharing is one way in which users of computers may share resources, such as documents, software programs, and the like, with other computer users on a network. Generally, a user of a host computer, server, or other computing device designates some or all of the files on the computing device as shared files, which may be viewed and downloaded by other users of the network (known as clients). However, existing file sharing services have limited functionality and are generally not extensible to allow the functionality of the file sharing service to be easily expanded by developers.